As the AP reports, Mills ran three times for president and finally emerged the victor in 2009, promising to reform the West African country.

The AP adds:

"Chief of Staff John Henry Martey Newman also addressed the nation on state-run television stations GTV and TV3, saying that Atta Mills died Tuesday afternoon at the 37th Military Hospital in Accra. Newman gave no details about the cause of Atta Mills' death.

"The president celebrated his 68th birthday Saturday. He was poised to seek re-election later this year."

France24 reports that constitutionally, the vice president will assume power. "Presidential elections are set for December in a country seen as a rare example of stable democracy in West Africa," Frane 24 adds.